1LTA: Heat-labile enterotoxin, subunit B

Name: PDB 1LTA: 2.2 Å crystal structure of E. Coli heat-labile enterotoxin (LT) with bound galactose
Published: 1994-01-31
License: https://creativecommons.org/publicdomain/zero/1.0/
Keywords: enterotoxin

2.2 Å crystal structure of E. Coli heat-labile enterotoxin (LT) with bound galactose. Determined by X-ray diffraction at 2.2 Å resolution. Released 31 Jan 1994.

Method: X-ray diffraction
Resolution: 2.2 Å
Organism: Escherichia coli
Chains: 7
Atoms: 6,390
Mol. weight: 87.52 kDa
Ligands: GAL
Released: 31 Jan 1994

Explore 1LTA in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

1LTA contains 39 α-helices and 45 β-strands across 7 chains. Residue ranges use author residue numbering, as in the PDB file, from PDBe. To see them in 3D, choose the Cartoon representation with Secondary structure coloring: helices, sheets and coils get different colors.

Chain A: 16 helices, 11 β-strands

Element	Residues	Length	Sheet
β-strand	4-9	6	4
α-helix	13-19	7
β-strand	21-22	2	5
α-helix	23-24	2
α-helix	41-46	6
β-strand	59-62	4	6
β-strand	63	1	4
α-helix	66-76	11
β-strand	82-89	8	4
β-strand	94-96	3	6
α-helix	97-101	5
α-helix	102-104	3
α-helix	108-110	3
β-strand	113-116	4	6
β-strand	119-120	2	5
α-helix	121-123	3
β-strand	124-131	8	4
β-strand	134-135	2	4
α-helix	139	1
β-strand	140-141	2	4
α-helix	142	1
α-helix	147-151	5
α-helix	155-157	3
α-helix	158-162	5
α-helix	172-175	4
α-helix	179-182	4
α-helix	183-184	2

Chain C: 3 helices, 0 β-strands

Element	Residues	Length
α-helix	197-222	26
α-helix	223-226	4
α-helix	232-236	5

Chain D: 4 helices, 6 β-strands

Element	Residues	Length	Sheet
α-helix	5-10	6
β-strand	15-22	8	1
β-strand	26-30	5	1
β-strand	38-41	4	1
β-strand	47-50	4	1
α-helix	51-53	3
α-helix	59-78	20
α-helix	80-81	2
β-strand	82-88	7	1
β-strand	94-102	9	1

Chain E: 4 helices, 6 β-strands

Element	Residues	Length	Sheet
α-helix	5-9	5
β-strand	15-22	8	1
β-strand	26-32	7	1
β-strand	35-41	7	1
β-strand	47-50	4	1
α-helix	51-53	3
α-helix	59-77	19
α-helix	80-81	2
β-strand	82-88	7	1
β-strand	94-102	9	1

Chain F: 4 helices, 8 β-strands

Element	Residues	Length	Sheet
α-helix	5-9	5
β-strand	15-22	8	1
β-strand	26-30	5	1
β-strand	32	1	2
β-strand	35	1	2
β-strand	38-41	4	1
β-strand	47-50	4	1
α-helix	51-53	3
α-helix	59-78	20
α-helix	80-81	2
β-strand	82-88	7	1
β-strand	94-102	9	1

Chain G: 4 helices, 8 β-strands

Element	Residues	Length	Sheet
α-helix	5-9	5
β-strand	15-23	9	1
β-strand	26-30	5	1
β-strand	32	1	3
β-strand	35	1	3
β-strand	38-41	4	1
β-strand	47-50	4	1
α-helix	51-53	3
α-helix	59-78	20
α-helix	80	1
β-strand	81-88	8	1
β-strand	94-102	9	1

Chain H: 4 helices, 6 β-strands

Element	Residues	Length	Sheet
α-helix	5-9	5
β-strand	15-22	8	1
β-strand	26-32	7	1
β-strand	35-41	7	1
β-strand	47-50	4	1
α-helix	51-53	3
α-helix	61-77	17
α-helix	80-81	2
β-strand	82-88	7	1
β-strand	94-102	9	1

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Heat-labile enterotoxin, subunit B	D, E, F, G, H	protein	103	Escherichia coli	P32890 (AlphaFold model)
Heat-labile enterotoxin, subunit A	A	protein	188	Escherichia coli	P06717 (AlphaFold model)
Heat-labile enterotoxin, subunit A	C	protein	49	Escherichia coli	P06717 (AlphaFold model)

Sequence of entity 1 (D, E, F, G, H), FASTA

>1LTA_1 HEAT-LABILE ENTEROTOXIN, SUBUNIT B (chains D, E, F, G, H)
APQTITELCSEYRNTQIYTINDKILSYTESMAGKREMVIITFKSGETFQVEVPGSQHIDS
QKKAIERMKDTLRITYLTETKIDKLCVWNNKTPNSIAAISMKN

Sequence of entity 2 (A), FASTA

>1LTA_2 HEAT-LABILE ENTEROTOXIN, SUBUNIT A (chains A)
NGDRLYRADSRPPDEIKRSGGLMPRGHNEYFDRGTQMNINLYDHARGTQTGFVRYDDGYV
STSLSLRSAHLAGQSILSGYSTYYIYVIATAPNMFNVNDVLGVYSPHPYEQEVSALGGIP
YSQIYGWYRVNFGVIDERLHRNREYRDRYYRNLNIAPAEDGYRLAGFPPDHQAWREEPWI
HHAPQGCG

Sequence of entity 3 (C), FASTA

>1LTA_3 HEAT-LABILE ENTEROTOXIN, SUBUNIT A (chains C)
RTITGDTCNEETQNLSTIYLREYQSKVKRQIFSDYQSEVDIYNRIRDEL

Ligands and cofactors

ID	Name	Formula	Copies
GAL	beta-D-galactopyranose	C6 H12 O6	5

Primary citation

Galactose-binding site in Escherichia coli heat-labile enterotoxin (LT) and cholera toxin (CT). Merritt, E.A., Sixma, T.K., Kalk, K.H. et al. Mol Microbiol (1994) 13:745-753. DOI 10.1111/j.1365-2958.1994.tb00467.x · PubMed

Other PDB entries of the same protein (UniProt P32890 (AlphaFold model), which also has an AlphaFold model), best resolution first:

1DJR 1.3 Å, Heat-labile enterotoxin B-pentamer complexed with M-carboxyphenyl-alpha-D-galactose
6IAL 1.45 Å, Porcine E.coli heat-labile enterotoxin B-pentamer in complex with Lacto-N-neohexaose
1EFI 1.6 Å, Heat-labile enterotoxin B-pentamer complexed with para-aminophenyl-alpha-D-galactopyranos…
5LZI 1.6 Å, Porcine heat-labile enterotoxin R13H in complex with inhibitor MM146
1LT5 1.7 Å, Heat-labile enterotoxin B-pentamer complexed with thiodigalactoside
1EEF 1.8 Å, Heat-labile enterotoxin B-pentamer complexed with bound ligand pepg
1FD7 1.8 Å, Heat-labile enterotoxin B-pentamer with bound ligand BMSC001
2XRS 1.81 Å, Crystal structures exploring the origins of the broader specificity of escherichia coli…
1LTS 1.95 Å, Refined structure of E. Coli heat labile enterotoxin, a close relative of cholera toxin
1PZI 1.99 Å, Heat-Labile Enterotoxin B-Pentamer Complexed With Nitrophenyl Galactoside 2a
1LT3 2.0 Å, Heat-labile enterotoxin double mutant N40C/G166C
1LT4 2.0 Å, Heat-labile enterotoxin mutant S63K

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